Structure of the radial parenchyma of annual shoots of wild species of mountain ash (Sorbus tianschanica Rupr.)

A S Bakhtaulova1 , A Abdildauly, T K Ukusheva, A M Atabayeva

Zhetysu University named after I. Zhansugurov, Taldykorgan, Introduction • The species Tian Shan mountain Ash (Sorbus tianschanica Rupr.) belongs to the genus Sorbus L. of woody plants from the Rosaceae family. In total, there are more than 100 species of mountain ash, of which about a third grows on the territory of the former USSR, the Republic of Kazakhstan-3 species.

• The main and natural distribution area of the species is in , in the mountain systems of the Tien Shan and Dzungarian Alatau in Kyrgyzstan and Kazakhstan.On the territory of the Trans- Ili Alatau and Dzungarian Alatau, Tian Shan mountain ash grows at altitudes of 1300-3600 m above sea level in the undergrowth of sparse spruce, spruce-deciduous, deciduous forests, juniper forests.

• Rowan Tian shan - deciduous shrub, rarely a small tree 4-5 m high. Overwintering buds are pubescent. Crown is thick, oval. The Sorbus tianschanica Rupr. shoots are first pubescent, then shiny, red-brown.

• The species is frost-resistant to minus 23°C, light-and moisture- loving.

• The study of the features of the anatomical structure of annual shoots allowed us to determine the features of the cytological structure of the stem of the annual shoot, to gain knowledge on the structure of the radial parenchyma, which is of great practical importance in the vegetative reproduction of this species. Materials and methods

• The object of the study was the annual shoots of Tian Shan rowanberrycollected in the territory of the Small Baskan cordon of the Dzhungar-Alatau state natural Park. • Cytohistological studies were carried out on equipment and with the help of chemicals from the bioresources laboratory of the research Institute of biotechnology problems. Anatomical sections were made on a sledge microtome with a thickness of 25 to 50 microns. The color of the slices was carried out blue water and chrysoidine for the division M.N. Prozina • The cellular organization of the medullary rays was studied on the transverse and longitudinal tangential and radial sections of the internodes of the stem, which allowed us to study in detail the addition of the radial parenchyma and measure both the rays themselves (row, layer and length) and their constituent parenchymal cells (width, height and length). Calculation, measurements and description of medullary rays were performed using the method of A. A. Yatsenko-Khmelevsky. The parameters of the medullary rays were determined by the number of ray cells and in micrometers, and the size of the ray cells – in micrometers. • Statistical processing of the obtained data was carried out using generally accepted methods in biometrics. Results and discussion

Dimensions of plant tissues and complexes on a cross-section of a year-old shoot of Tian Shan mountain ash in microns (x 100)

Core (1/2 radius) Perimedullary Xylem Cambial zone Primary cortex Cork Total length zone

520 111 934 40 382 34 2021

25.7% 5.5% 46.2% 2.0% 18.9% 1.7% 100.0%

The Number of core rays in the wood of the annual shoot of Tian Shan mountain ash (X400) Indicators of the radial parenchyma Cross section Tangent section Quantity % Quantity % Total number of rays per slice 264±2.3 100.0 14.0±1.0 100.0 Primary rays 264±2.3 100.0 - - Among them single row 236 ±3.4 89.1 11.0±0.3 78.6 Double-row 20 ±1.4 7.6 2.0±0.6 14.3 Three-row 4±0.4 1.7 1.0±0.6 7.1

Four-row 4±0.4 1.6 - -

Dimensions of ray cells of the core rays of the wood of the Tian Shan mountain ash stalk on anatomical sections, microns

Directions of anatomical sections of the stem Cross Longitudinal Tangential Radial Width Length Height Breadth Length Height 7.7 18.3 13.3 9.0 27.1 15.6 Conclusions: • The core and wood are clearly distinguished on the cross section of the stem of the annual shoot of the Tian Shan mountain ash. The wood contains a year-old layer of xylem, the radius of which is slightly uneven and has small protrusions in the perimedullary zone of the core.

• In the structure of the annual shoot, the radius of the core is 25.7%, xylem-46.2%, phloem-18.9%. Vessels of annual wood have an equalized diameter and their number decreases by the end of the growing season. Therefore, by the location and size of vessels, Rowan belongs to the breeds with scattered vascular core wood. Green cuttings they consist of a section of a stem with several leaves, so the axial parts have a secondary anatomical structure.

• On the cross-section, the stem of the Tian Shan mountain ash is characterized by very thin core rays. The radial parenchyma is represented by primary core rays. The cross section is dominated by single-row primary core rays (89.1%), multi-row rays are 10.9%.

• The core rays consist of cells stretched in a radial direction, the length of which is 2.0-2.2 times the width (recumbent cells). Square ray cells are located next to the perimedullary zone. On the tangent section of the stem of the annual shoot of the Tian Shan mountain ash, the ray parenchyma is represented by one-, two -, three-row rays. Single-row beams make up 78.6%, two - and three-row beams-21.4%. Most rays are built in square cells, and standing cells are only found at the end ends. The radial section of wood is dominated by recumbent cells, square cells are located near the perimedullary zone of annual growth.

• When averaging all parameters of the ray parenchyma of the Tian Shan mountain ash, an "average" cell is characteristic, having a ratio of width, length and height of 1 : 2.7 : 1.7, which indicates the addition of the core rays mainly by cells elongated in the radial direction. Based on the number of single - and multi-row rays and their addition by recumbent cells, the potential rootability of green cuttings will be about 20%.